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Earthquake Monitoring

The Earthquake Monitoring section is responsible for a number of core operational tasks. The section is led by Dr. John Clinton.

Together with the ELAB team (which installs and maintains field and communications infrastructure), the Earthquake Monitoring Group manages Switzerland's national seismic infrastructure (CHNet), which comprises the main monitoring network (SDSNet, originally comprising stations with broadband and short-period sensors, but now being upgraded to feature co-located broadband and strong-motion stations) and the predominantly urban strong-motion network (SSMNet). All stations operate high-dynamic-range sensors with wide frequency bandwidths and are digitised on modern 24 or 26-bit data loggers, which stream data in real time, targeting minimum latency. The Earthquake Monitoring team is responsible for guaranteeing the real-time communications of these over 200 stations; managing and processing any data that arrives in Zurich; and assessing quality to ensure that the data are ready to use to produce an Earthquake Catalogue and in downstream research. Stefan Heimers and Roman Racine are the main team members responsible for these tasks.

The Seismic Network team also works with SED colleagues to manage the instruments pool that can be used for both research and emergency purposes. The instrument pool consists of over 50 broadband stations. Recent major projects include deployments in Bhutan, Greenland, Greece and Central America. Most of the instruments are currently being deployed across various Alpine nations as part of the AlpArray project. Other projects involve stations monitoring on Swiss glaciers and the sites of major landslides. The aftershock pool consists of around ten readily available high-quality infrastructure that can be deployed across Switzerland within hours of a significant earthquake, under the leadership of Dr Toni Kraft. The majority of stations in the instrument pool are equipped with real-time cellular communications and are seamlessly integrated into our monitoring system.

Real-time monitoring of the seismic network infrastructure is one of the group's key functions. Our core task is to monitor Switzerland's seismicity using the monitoring stations belonging to our dense national networks, complemented by temporary stations and equivalent facilities operated by partners in neighbouring countries. We are responsible for all real-time processing of earthquake data in Switzerland. The main software we use for this purpose is SeisComP3, a very popular and widely used open-source solution for monitoring seismicity, which we are continually enhancing. Our active research team manages the system's operational configuration and evaluates new methods for detecting and improving characterisations of seismicity (Dr Tobias Diehl). We also develop novel approaches to earthquake early warnings and rapid source characterisation (Dr Maren Böse and Dr Frédérick Massin); estimating strong ground motions and their impacts (Dr Carlo Cauzzi); and monitoring induced seismicity (Luca Scarabello). A key concern of our group is to transform these approaches into operational software. We also monitor the network's state of health and, helped by the ELAB team, try to optimise its performance.

Although our main focus is on Switzerland, we also develop techniques that can be applied elsewhere, teaming up with agencies around the world to develop and install EEW and monitoring systems California, Central America and Chile, for example. The open-source EEW software modules we develop, including an EEW Display tool, are compatible with SeisComP3 and can thus be readily adopted by many seismic networks across the globe.

In addition to operating real-time monitoring infrastructure, our group also leads SED's team of on-duty seismologists who react to detected significant events, providing rapid manual verification. This team also creates and curates the national earthquake catalogue, which is updated within hours to a few days. Philipp Kästli from the IT team develops and operates the earthquake alert software that immediately notifies the media, authorities, the public, the Swiss Seismological Service (SED) and interested scientists of seismic events that may be of significance to Switzerland. We also notify the Swiss authorities of large-scale teleseismic events that could have a significant local or regional impact.

The Seismotectonics research group is led by Dr Tobias Diehl and analyses seismic data to gain a clearer understanding of the subsoil and the tectonic context. The main focus of the group's research is the Swiss Alps and their foothills, though its members are also involved in many international projects, for example – at the time of writing – in Bhutan and in the AlpArray project. For example, recordings of local, regional or teleseismic earthquakes can be used in a tomographic analysis to produce 3D representations of the velocity structure in the subsoil, whilst simultaneously pinpointing the location of such quakes with maximum accuracy. This also enables indirect conclusions to be reached about rock properties and physical parameters like density and temperature. Moreover, earthquakes' so-called dispersion characteristics can be used to make inferences about rupture processes or stresses in the subsoil.

NASA's InSight mission will land a science payload including a broadband seismometer package (SEIS) on Mars in November 2018. Building on our expertise and infrastructure for earthquake monitoring and seismic data processing on Earth, the Earthquake Monitoring group is assuming the lead role in the Marsquake Service that will build a catalogue of seismic events from the data recorded by SEIS. Dr John Clinton, Co-Investigator on the InSight project, will coordinate this service, assisted by Dr Maren BöseDr Savas Ceylan and Dr Fabian Euchner. The Marsquake Service will include both automatic and reviewed event detection and the characterisation of local seismicity and teleseismic events, as well as meteor impacts. The goal of this service is to create a comprehensive high-quality event catalogue for Mars, itself a critical target for the InSight mission, and provide key input for the development of Martian crustal and deep-structure models. We are adapting advanced single-seismometer analytic techniques developed for applications on Earth to make them suitable for characterising Martian seismicity. The Marsquake Service will be a joint effort by the SED and the SEG groups at the ETH Zurich, led by InSight Co-Investigator Professor Domenico Giardini, Dr Martin van Driel and Dr Amir Khan. The service is also part of a broader SEIS Science and Service initiative coordinated by Professor Philippe Lognonné at the Paris Institute of Earth Physics (IPGP).